The present invention pertains to cranes and, more particularly, to cranes used in the manipulation of equipment submerged in the water of a boiling water nuclear reactor (BWR).
Movement of equipment and components of a boiling water reactor is accomplished by the use of a heavy-duty overhead crane which comprises a part of the reactor system. Due to the limited space available within the pressure vessel and the geometry of the pool within which the loads are located, it may sometimes be necessary to lower the crane hook below the water surface. Because the water is radioactive, it is undesirable to wet the crane hook, hook block or cables therein, as they must then be thoroughly washed or otherwise decontaminated before they may be used again.
It is, therefore, a primary object of the present invention to provide a watertight cover for a crane hook, hook block and cables which does not interfere with the crane operation.
The foregoing and other objects and advantages are achieved by a watertight cover comprising a hook box, of a size to receive the hook, sealingly joined to a first cover member, which is of a size to receive the hook block. A second cover member is telescopically carried on the first cover member. Remotely controlled means are provided for displacing the second cover member, relative to the first cover member, as the hook is lowered into the water.
Advantageously, the hook box is integrally formed with a load-supporting strongback. Likewise, the first cover member may be integrally formed with the hook.